Your student loan comes with either a variable or fixed interest rate. If it’s fixed, you don’t have much to worry about (aside from the whole crushing debt thing). But if you have a variable rate loan, that rate can change along with different economic factors—the stock market, for example.

Your student loan’s variable rate is indirectly tied to certain influences in the economy. The stock market is one of them, explains Forbes’ Stephen Dash. And when it changes, that might be cause for your lender to increase your rate (which means you’ll pay more every month). Here’s how he explains it:

The interest rate charged on variable-rate student loans is typically tied to the London Interbank Offer Rate (LIBOR). LIBOR indirectly tracks the interest rate set by the Federal Reserve, and has historically been highly correlated with the Feds actions. Interest rates on federal student loans are determined once a year, when they’re benchmarked against yields on 10-year U.S. Treasury bonds auctioned in the month of May...In environments of weaker economic growth, they typically use lower interest rates to incentivize individuals and businesses to borrow and consume – promoting stronger economic growth. Conversely, in environments of strong economic growth, they will raise interest rates to curb investment and consumption.

As Dash points out, the Fed’s decision to raise rates (and they’re expected to by the end of the year) will impact your student loan rate, and indirectly, so can the stock market. It’s something to be aware of if you have a variable loan. For more detail, read his full post at the link below.